Power conversion apparatus

Provided is a power conversion apparatus, wherein short-circuiting malfunctions of capacitors serially connected within a smoothing capacitor circuit (4) can be detected. A capacitor malfunction detection circuit is composed by combining switching units (7SW), excitation resistors (8R), contact resistors (9R), and diodes (10D). Each of the switching units (7SW) is provided with an excitation circuit and a contact circuit, and the contact circuit closes when a prescribed current flows through the excitation circuit. Both the excitation circuit of the switching unit (7SW) and the excitation resistor (8R), and the contact circuit of the switching unit (7SW) and the contact resistor (9R), are connected in series for the number of capacitors connected in series, and these serially connected circuits are connected parallel to the capacitors. The connection points between the excitation resistors (8R) and the next switching units, and the connection points between the contact resistors (9R) and the next switching un